Air-compressor.



No. 657,025. Patented, Aug, 28', I900.

E. HUBN.

AIR COMPRESSOR.

(Application filed June 1, 1900.;

3 Sheets-Sheet I.

(No Model.)

m: mums PKTERS cc FHoTo uTNO, WASHINGTON, u. c

No. 657,025. Patented Aug. 28, l900.

E. HURN.

AIR COMPRESSOR.

(Application filed June 1. 1900.) (No Model.) 3 Sheets-+Sh0i2t 2.

Patented Aug. 28, I900.

3.Sheets-Sheet 3.

E. HURN.

AIR COMPRESSOR.

(Application filed June 1I 1900.;

rm: noams PEYzRs co. mom-u ma. WASHINGTON, b. c.

(No Model.)

UNITED STATES PATENT OFFICE.

EDWARD HURN, OF TROWBRIDGE, ENGLAND, ASSIGNOR TO JOSEPH POYNTON HADEN, OF SAME PLACE.

AIR-COMPRESSOR.

SPECIFICATION forming part of Letters Patent No. 657,02 5, dated August 28, 1900.

Application filed June 1, 1900.

To all whom it may concern:

Be it known that I ,EDWARD HURN, mechanic,a subject of the Queen of Great Britain and Ireland, residing at Trowbridge, in the county of Wilts, England, have invented certain new and useful Improvements'inAir-Oompressors, of which the followingis a specification.

This invention refers to air-compressors, whether belt-driven or otherwise, in which the power is automatically thrown out of gear by a trip or other mechanism when the pressure in the receiver attains a certain magnitude and is put in operation again by the same or other mechanism when the pressure falls.

The object of the invention is to allow the compressor to get fairly running before the full load, due to the full pressure in the receiver, comes on the piston or plunger of the air-cylinder and to relieve it from the necessity of working against the full load from the moment when it is put in operation by the automatic mechanism.

I attain the above object by means of a relief valve and pipe directly connected to the deli very-pipe of the air-compressor. The out let of this pipe is open to the atmosphere and is controlled by the relief cock or valve. This valve is operated by a system of levers and links connected to the mechanism, which throws the power out of gear in such a way that when the power is out of gear the reliefvalve is open and when in gear the valve is closed. An auxiliary check-valve is in all cases inserted in the delivery-pipe between the receiver and the relief-valve or at the receiver end of the delivery-pipe. These means applied to a belt-driven air-compressor, to which type the invention is especially applicable, are illustrated in the accompanying drawings.

Figure 1 is a side elevation; Fig. 2, a plan. Fig. 3 is an end elevation at the line A A looking to the right of Fig. 1 and left of Fig. 2.

a a indicate the air-compressing cylinders, and b b and c the delivery-pipes from the same to the receiver d.

c and f are the loose and fast pulleys, respectively, and g is the belt-shifting fork of the driving arrangements.

h is the controlling-cylinder, provided with Serial No. 18,760. (No model.)

a loaded piston, 2' indicating the load on the lower end of the piston-rod The lower end of the cylinder h is placed in communication with the interior of the receiver (Z by means of the pipe 70. The upper end of the pistonrod j is connected to the pin Z, projecting from the upper side of the sliding block m, carrying the belt-shifting fork g, by means of the cross-head n, lever 0, connecting-rod p, bell-crank lever q 9, link 3, and horizontal lever 15, a hole in one end of the lever 15 being provided for the insertion and engagement of the pin Z and a hole in one end of the link 3 being provided for the insertion and engagement of the pin-arm r of the bellcrank lever q r. The levers o, q r, and t are carried and hinged about the brackets u, 'v, and w, respectively.

It will be seen that the above connections are such that when the pressure in the airreceiver d is less than that necessary to keep the loaded piston raised the piston-rod j is drawn and kept down by the load 1', which through the mechanism just mentioned moves and keeps the belt to and on the fast pulley f, as indicated in Fig. 2. As soon as the pressure in the receiver d rises sufficiently to raise the loaded piston the same connections move the belt onto the loose pulley e. The load on the piston-rod is adjusted so that the rise of the piston takes place when the pressure in the air-receiver reaches the normal or predetermined pressure.

Thus far the working of the air-compressor is not novel.

so is the above-mentioned relief-pipe, and g the relief-valve, fitted in the valve-box z.

1 is the auxiliary check-valve, fitted at the receiver end of the delivery-pipe c.

The delivery-pipes b b from the two com pressor-cylinders a a and the delivery-pipe c to the air-receiver d are all connected to the valve-box 2 above the relief-valve y. The relief-valve y is connected, by means of the rod 2 and lever 3, hinged on the standard 4, to the cross-head n of the piston-rod'j of the controlling cylinder, the connection being such that the relief-valve y is closed as the piston-rod j lowers and opened as the pistonrod j rises-that is, the reliefwalve y is closed so long as the pressure in the receiver (l remains below the normal or predetermined magnitude and is opened as soon as the pressure in the receiver reaches this magnitude.

The working of the invention is as follows: When the belt-fork g shifts the belt from the loose pulley e to the fast pulley f, the reliefvalve y, previously full open, is suddenly closed, and the pressure in the delivery-pipes b b and c is at first small during the time that the cover or grip of the belt on the fast pulley f is slight, and the pressure gradually rises, at first from atmospheric pressure,with each stroke, owing to the delivery-pipes b b and c forming a small auxiliary receiver, up to the pressure in the main receiver d, thus allowing the compressor to attain its normal speed before the air-pressure in the deliverypipes reaches the predetermined maximum pressure in the receiver. The delivery-pipes are made of such a size or capacity that the pressure rises to this magnitude in such a number of revolutions as will enable the compressor to get fairly running.

I wish it to be understood that the mechanism for automatically throwing the power out of gear when the predetermined pressure has been attained in the receiver does not form part of my invention and that other kinds or arrangements of such mechanism may be employed for this purpose; but

What I claim as new, and desire to secure by Letters Patent, is

1. In air-compressors in which the power is automatically thrown out of gear when the pressure in the receiver reaches a predetermined magnitude, the combination with the delivery-pipes such as b b and 0 leading from the compressor to the receiver of a reliefvalve y in the delivery-pipe connected to the automatic throwing-out mechanism to be operated thereby and a check-valve 1 at the end of the delivery-pipe, substantially as set forth.

2. In air-compressors in which the power is automatically thrown out of gear by a controlling-cylinder communicating with the receiver and having a loaded piston, the combination with the delivery-pipes such as b b and c of a check-valve l a relief-valve y valverod 2 lever 3 cylinder h loaded piston and rod j and pipe is, substantially as set forth.

EDVARD HURN.

\Vitnesses:

U. H. BARKER, P. E. CoULsoN, P. B. L. WILNER. 

